The present invention relates to minute particle loading method and apparatus, and more particularly to a method and an apparatus for supplying and loading solder balls into a jig having holes which are in the same array as solder ball connected portions (or connecting pads) of a semiconductor device and are to receive the solder balls, when the solder balls are joined to the solder ball connected portions of the semiconductor device.
The present invention also relates to solder bump forming method and apparatus for forming solder bumps at the solder ball connected portions by melting the solder balls.
The present invention further relates to a method and an apparatus for manufacturing a semiconductor module in which the solder bumps are formed by the above methods and apparatus.
Japanese Patent Unexamined Publication No. 60-52045 discloses a method of supplying and arraying solder balls into predetermined positions.
The disclosed method is illustrated in FIG. 40a-40d. This method comprises the step of 40a, locating a positioning plate 9004 having insertion holes 9003, into which particles 9000 such as solder balls are to be placed, with respect to electrode pads 9002 on a substrate 9001 such that the insertion holes 9003 locates just above the respective electrode pads 9002, FIG. 40b, supplying the particles 9000 on the positioning plate 9004 and vibrating the positioning plate 9004, FIG. 40c, causing the particles 9000 to be fitted in the respective insertion holes 9003 upon the vibration, and FIG. 40d, discharging the surplus particles 9000 by tilting both the positioning plate 9004 and the substrate 9001 at the same time.
However, the above method suffers from the following problems. First, even once the particles are fitted in the respective insertion holes of the positioning plate, the particles may slip off from the holes when the positioning plate is vibrated or tilted, because no means exist for retaining the particles in the insertion holes. This results in the reduced hit rate in a loading operation of the particles. Secondly, the particles and the positioning plate may be charged with static electricity, causing the particles to adhere to each other or to the positioning plate, resulting in difficulty loading the particles in the desired amount and positions. Thirdly, tilting the positioning plate makes the mechanism more complex. Finally, since the surplus particles scattering flow, difficulty is encountered in recovering the particles.
One of bump forming methods is disclosed in Japanese Patent Examined Publication No. 64-819, for example.
As shown in FIGS. 41-43, this disclosed method pertains to a technique of forming solder bumps on respective connecting pins 115 extended to penetrate through a ceramic substrate 111. First, a predetermined amount of flux 118 is coated on a head of each of the connecting pins 115 by a flux dispensing apparatus 117. Then, solder balls 125 are placed in a container 126 disposed on a vibrator 127, and are suctioned by a suction mask 133 of a vacuum-suction apparatus 128. The solder balls 125 thus suctioned, rest on the respective heads of the connecting pins 115 coated with the flux 118. After de-energizing the vacuum-suction apparatus, vibration is applied, separating the solder balls 125 from the suction mask 133. The solder balls 125 remaining held on the respective heads of the connecting pins 115 due to adhesion forces of the flux 118.
The solder balls adhering to the connecting pins can be melted by bringing the ceramic substrate with the solder balls adhering thereto into a furnace and heating the solder balls under preset temperature control, as described in Japanese Patent Unexamined Publication No. 62-257737 by way or by of example, or by condensing a laser beam to the small diameter and scanning the laser beam over the particular solder balls.
However, such a conventional solder bump forming method suffers from the problems as follows. When the solder balls are separated from the suction mask upon the vibration, or when the ceramic substrate with the solder balls adhering thereto is conveyed into the furnace for melting the solder balls, the solder balls may be shifted in their positions. Also, unless the coated amount and viscosity of the flux are properly controlled, the flux could be dried so that the solder balls would be shifted in their positions. In some cases, the dried flux might even cause the solder balls to drop off when they are melted.
As mentioned above, because the solder balls are retained by only the adhesion forces of the flux, the conventional solder bump forming method is problematic in that the solder balls are easily shifted and the solder bumps cannot be formed in desired positions.
Further, the method of bringing the ceramic substrate into the furnace to melt the solder balls takes time for conveying the ceramic substrate. Alternatively, the method of condensing the laser beam to the small diameter and scanning the laser beam over the solder balls takes time until all the solder balls are melted, because the laser beam is partially irradiated at one time and scanned to cover all the solder balls. Thus, the conventional solder bump forming method is also problematic in taking time to convey the ceramic substrate or melt all the solder balls and, as a result, increasing the time required for forming the solder bumps.